<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>css7样式</title>
		<style>
			
			
			.c2{
				border: 2px solid gold;
				color:green;
			}
			.c3{
				color:blue;
			}
			.c1{
				font-size: 40px;
				color: red;
			}
		</style>
	</head>
	<body>
		<h1 class="c3 c1 c2">class可以多个</h1>
	</body>
</html>